Spark plug



Patented May 22, 1923.

it@ 'that -tiitl VVILTON F. JENKIS, OF RICHMOND, VIRGINIA..

SPARK PLUG. I

Application led June 23, 1920. SerialiNo. 391,112.

To ([Z w from it may concern Be it known that I, ILTON F. JENKINS, a citizen of the United States, and a resident of Richmond, in the county ot Henrico and State of Virginia, have inventedl certain new and useful Improvements in 'Spark Plugs, of which the following is a speciiication. y v

My invention relates to improvements in spark plugs, and it consists in the constructions, combinations and arrangements herein described and claimed. y

One ot the foremost objects of the invention is to provide a spark plug `embodying certain improvements by the use ot' which the central electrode is more iirmly locked in position, a better electrical contact with the Connected high tension vwire is secured, and by means of which premature discarding of the plug -is obviated.

More specifically, one of the above objects resides in providing a screw head of an un usual construction, one ot its functions being to scrape away foreign matter from the terminal plate of the connected wire as said head is screwed down, so as .to provide v'for itseli5v a clean electrical contact.

further object 0i the invention is to provide in combination with the above screw head, lateral spindles which are employed as spark gap gages.

A further object of the invention, and one which ot necessity is closely related to some of the l'foregoing objects, is to provide a screw head for a spark plug, of such a shape that it cannot Afall into the spark plug opening in the engine when the plug is removed, and thus cause later trouble. V j

Other objects and advantages will appear in the following specification, reference being had to the accompanying drawing in which: f f v kFigure 1 is a side elevation of the improved spark plug,

Figure 2 is a plan view thereof, the screw head. beingremoved so as to `show the improved lock for the central electrode,

Figure 3 is a detail perspective view ot the upper portion of the spark plug, showing the various members of the above lock,

Figure 4 is a plan view illustrating how a place is cleaned or scraped on the terminal plate of the connected wire as the head is screwed into place,

#Figure 5 is a detail perspective view of the screw head, the lateral gage spindles being clearly shown,

l -Figure 6 is an inverted plan view oi kthe spark plug, showing the improved. edge electrode, and

Figure 7 is a perspective view oi a part ,l

ot' an engine, showing how it is impossible for the screw head to fall through thesparlr plug opening.,` f

Considering first the general spark plug construction, it is to be observed that it con` l sists of the non-circular part l by means of -which the threaded sleeve '2 is screwed into the usual opening 3 of the engine t.' These parts are of` the ordinary construction, but thel porcelain core 5 is slightly modified in that it is provided with a recess 6 at the upper edge, in which the lower lip 'i' of the lock washer 8 seats. f

- rIhe upperlip 9 of this lock washer, en-

gages one of the 'faces of the jamb nut 10,`

and since a spring washer 11 is interposed between the washer 8 and. nut 10, all loosening of the associated parts is .positively pre lvenited. These parts are fitted onthe upper threaded end of` the central electrode` 1Q.l

The spring washer 11 compensates for eX- pansionand contraction, and lthe lock washer 8 preventsturning either of the nut 10 or the electrode 12.

Special attention is directed to the construction o'f the screw head 13. The main body thereof is made square but may belet' another non-circular shape; The purpose of making the body non-circular, is to insure the cleaning or scraping of a good elec trical contact on` the terminal plate '140i the high tension wire 15, whenthe head 13 is screwed down as vshown in Figure 4E.

It is not uncommon that difficulties are encountered inthe operation of an engine simply because of a poor electrical Contact at some place in the ignition circuit. It often happens that the terminal pl'zutesfoi the high' tension wires become so coatedthat is gotten to accomplish the final turning of y the screw head.

Gages 18 andl) are foi-.med on the eX- tremities of the spindles 17;

is eniployed in the ignitioncircuit, as indif cated by the` initial letterM, tl'ie'latter being used to gage the spark gap when a battery is employed in the ignition circuit, as

indi-cated by the initial letterB. 'l

`Both gage points are cl-ii'sel'shaped'ras.

clearly shown in Figure el., but lthe` gage 19 `is additionally sharpened at20- to provide alscrapiiigvedge whichv *i'sfusefull in making a clean contact place on such part whereon '-itinay be found'expedient 4to usegit. l

Attention is now directed-tol the construc tion of thespark gap. The central electrode V12 is of a,l usual construction, Abut the edge electrode 21 is made of a substantial V-shape so as 'to produce two legs 22 which are respectivelygrounded in thebodyfof the spark lug at'separate places. @bviously it will e with,considerablediliiculty that the elec- [trede 21 couldfbe dislodged, andv it is contemplatedithat this forni of electrode will survive any ordinary and even moderately rough use of spark plug.l

which is tohbe'adjusted by bending-the .electrode r12 in theproper.l direction until' the space .isfixed according to that oneoithe points used vasia gage. The spark gap Slightly greater for battery current than it is when vcurrent fromv a magneto Ai'svused.

Figureiv illustrateshow impossible it is rfor the screw head-13 to fall into thespark plug opening 3 of the le'ngiif'ieje.I Naturally this is by reason of thefact that the screw head is of considerable; size, and at. any

event, larger than the hole fortlie sleeve 2.

, In constructionsvof'y well known vvtypes of vspark plugs, relatively smallbinding nuts are used to fasten the high place.v y y. f It often happens that `in` making adjust tension wires in v'ments about his engine, an' operator will. lay vthis blindlngnut on the head of the engine,

and it ,movinf about brush it into theopen Ahole Obviously` `trouble will commence .when attempting'torun the engine witha metallic piece in the compression or working chamber, which ought to be clear. The

special construction ot' the screw head, while not intended primarily to avoid the lessot the usual bindingv nut, does prevent "any damagewhich might occur by the falling large size as indicated I claim 4olf such nut vinto therv engine, because ofits above.

The one 18 thinner than the one 19, the it'ormergbeing used to vgage the spark gap when a magneto In using the gage points 118k and 19, one or the other Vis tobe inserted into the gapY G' '1. A bindingv screw for spark'plugs, etc.

with iioncircular portions for scraping a clean contact seat on a terminal plate, wnen screwing it into place. f

2. r1 spark plug, including a central elec` ti'od'e and the terminal plate of a high tension wire fitted thereon, and a screw head arranged to produce a clean contact on said plate as it is screwed 'thereagainstonsaid electrode. 1 p i 3., A spark plug, including a screw head with an upper knobffor initially twirling the head on the threaded end of a central electrode, and a non-circular vbase providing cutting edges for producing a clean contact seat when thehead is screwed into engage'7 ment'with a terminal plate. 4 f 'y a. A spark plug, including a screw head with an upper knob "for initially'twirling theliead ontlie threaded end of 'a central electrode, a non-circular'base providing cutting edges for producinga clean contactseat when the. headfisscrewed into engagement screw lieadjenabling obtaining a leverage in finally turningl to avoid the use of a wrench or the like. Y y i 5. A spark plug, including a screw head the head on the threaded end ofva central [the electrode engaged lby vanother lip of s aid washer to prevent turning,` and a 'spring lwasher between the lock nut and lockI washer with a terminal plate, andiiieansgonfthe `with an upperl Vknob for initially tw'irlfing el'ectrod'a non-circular base providing cut-'f v 100 incliitling an insulating to compensate forY erpansich andfcontrao tion.v l 1 y 8. A spark 4plug,including an insulating bushing with a recess, andarentral elec trede; a lock washer on they electrode with one `lip seated 1n thei'ecess, a'lock nut' onthe electrode engagedby `another lip off said washer to prevent ti'uii'ing, a spring'washer `between the lock Anut 'and lock washer to compensate ifoi'l expansion and contraction, and a :lie-ad. screwed on the electrode to bind the terminal plate of afwire against Jthe lock nut. VVILTON'F; JENKINS-` 

